This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cellular metabolism and redox state have been shown as key mediators in cellular metabolism, apoptosis and signaling transductions. Redox state information is useful for understanding pathology of diseases including cancer, diabetes, cardiovascular disease, and Parkinson's disease etc. In addition, the regulation of reactive oxygen species and redox state has been implicated in stem cell research. However, no direct observation of mitochondrial NAD-coupled redox state in stem cells has been reported. In this project we aim to employ the low temperature NADH/Fp (reduced nicotinamide adenine dinucleotide/oxidized flavoproteins) fluorescence imaging or "redox scanning" to image the in vivo mitochondrial redox states of stem cells and to investigate if there is any connection between mitochondrial redox state and pluripotency of stem cells.